/*
 *  Licensed to the Apache Software Foundation (ASF) under one
 *  or more contributor license agreements.  See the NOTICE file
 *  distributed with this work for additional information
 *  regarding copyright ownership.  The ASF licenses this file
 *  to you under the Apache License, Version 2.0 (the
 *  "License"); you may not use this file except in compliance
 *  with the License.  You may obtain a copy of the License at
 *  
 *    http://www.apache.org/licenses/LICENSE-2.0
 *  
 *  Unless required by applicable law or agreed to in writing,
 *  software distributed under the License is distributed on an
 *  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 *  KIND, either express or implied.  See the License for the
 *  specific language governing permissions and limitations
 *  under the License. 
 *  
 */
package org.apache.directory.shared.ldap.util;


import java.io.PrintStream;
import java.io.PrintWriter;


/**
 * An interface to be implemented by {@link java.lang.Throwable} extensions
 * which would like to be able to nest root exceptions inside themselves.
 * 
 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
 */
public interface Nestable
{

    /**
     * Returns the reference to the exception or error that caused the exception
     * implementing the <code>Nestable</code> to be thrown.
     * 
     * @return throwable that caused the original exception
     */
    public Throwable getCause();


    /**
     * Returns the error message of this and any nested <code>Throwable</code>.
     * 
     * @return the error message
     */
    public String getMessage();


    /**
     * Returns the error message of the <code>Throwable</code> in the chain of
     * <code>Throwable</code>s at the specified index, numbered from 0.
     * 
     * @param index
     *            the index of the <code>Throwable</code> in the chain of
     *            <code>Throwable</code>s
     * @return the error message, or null if the <code>Throwable</code> at the
     *         specified index in the chain does not contain a message
     * @throws IndexOutOfBoundsException
     *             if the <code>index</code> argument is negative or not less
     *             than the count of <code>Throwable</code>s in the chain
     */
    public String getMessage( int index );


    /**
     * Returns the error message of this and any nested <code>Throwable</code>s
     * in an array of Strings, one element for each message. Any
     * <code>Throwable</code> not containing a message is represented in the
     * array by a null. This has the effect of cause the length of the returned
     * array to be equal to the result of the {@link #getThrowableCount()}
     * operation.
     * 
     * @return the error messages
     */
    public String[] getMessages();


    /**
     * Returns the <code>Throwable</code> in the chain of
     * <code>Throwable</code>s at the specified index, numbered from 0.
     * 
     * @param index
     *            the index, numbered from 0, of the <code>Throwable</code> in
     *            the chain of <code>Throwable</code>s
     * @return the <code>Throwable</code>
     * @throws IndexOutOfBoundsException
     *             if the <code>index</code> argument is negative or not less
     *             than the count of <code>Throwable</code>s in the chain
     */
    public Throwable getThrowable( int index );


    /**
     * Returns the number of nested <code>Throwable</code>s represented by
     * this <code>Nestable</code>, including this <code>Nestable</code>.
     * 
     * @return the throwable count
     */
    public int getThrowableCount();


    /**
     * Returns this <code>Nestable</code> and any nested
     * <code>Throwable</code>s in an array of <code>Throwable</code>s, one
     * element for each <code>Throwable</code>.
     * 
     * @return the <code>Throwable</code>s
     */
    public Throwable[] getThrowables();


    /**
     * Returns the index, numbered from 0, of the first occurrence of the
     * specified type in the chain of <code>Throwable</code>s, or -1 if the
     * specified type is not found in the chain.
     * 
     * @param type
     *            <code>Class</code> to be found
     * @return index of the first occurrence of the type in the chain, or -1 if
     *         the type is not found
     */
    public int indexOfThrowable( Class type );


    /**
     * Returns the index, numbered from 0, of the first <code>Throwable</code>
     * that matches the specified type in the chain of <code>Throwable</code>s
     * with an index greater than or equal to the specified index, or -1 if the
     * type is not found.
     * 
     * @param type
     *            <code>Class</code> to be found
     * @param fromIndex
     *            the index, numbered from 0, of the starting position in the
     *            chain to be searched
     * @return index of the first occurrence of the type in the chain, or -1 if
     *         the type is not found
     * @throws IndexOutOfBoundsException
     *             if the <code>fromIndex</code> argument is negative or not
     *             less than the count of <code>Throwable</code>s in the
     *             chain
     */
    public int indexOfThrowable( Class type, int fromIndex );


    /**
     * Prints the stack trace of this exception to the specified print writer.
     * Includes information from the exception, if any, which caused this
     * exception.
     * 
     * @param out
     *            <code>PrintWriter</code> to use for output.
     */
    public void printStackTrace( PrintWriter out );


    /**
     * Prints the stack trace of this exception to the specified print stream.
     * Includes information from the exception, if any, which caused this
     * exception.
     * 
     * @param out
     *            <code>PrintStream</code> to use for output.
     */
    public void printStackTrace( PrintStream out );


    /**
     * Prints the stack trace for this exception only--root cause not
     * included--using the provided writer. Used by 
     * {@link "org.apache.commons.lang.exception.NestableDelegate"} to write individual
     * stack traces to a buffer. The implementation of this method should call
     * <code>super.printStackTrace(out);</code> in most cases.
     * 
     * @param out
     *            The writer to use.
     */
    public void printPartialStackTrace( PrintWriter out );

}
